Nicotine Levels in Electronic Cigarettes
TL;DR: In ECs, which vaporize nicotine effectively, the amount inhaled from 15 puffs is lower compared with smoking a conventional cigarette, but EC brands and models differ in their efficacy and consistency of nicotine vaporization.
Abstract: Introduction: The electronic cigarette (EC) is a plastic device that imitates conventional cigarettes and was developed to deliver nicotine in a toxin-free vapor. Nicotine in a solution is heated and vaporized when a person puffs through the device and is inhaled as a vapor into the mouth. The EC is a new product on the market and little is known about its safety and nicotine delivery efficacy. The aim of the study was to analyze nicotine levels in vapor generated from various EC brands and models. The study was designed to assess efficacy and consistency of various ECs in converting nicotine to vapor and to analyze dynamics of nicotine vaporization. Methods: Sixteen ECs were selected based on their popularity in the Polish, U.K. and U.S. markets. Vapors were generated using an automatic smoking machine modified to simulate puffing con ditions of real EC users. Nicotine was absorbed in a set of washing bottles with methanol and analyzed with gas chromatography. Results: The total level of nicotine in vapor generated by 20 series of 15 puffs varied from 0.5 to 15.4 mg. Most of the analyzed ECs effectively delivered nicotine during the first 150–180 puffs. On an average, 50%–60% of nicotine from a cartridge was vaporized. Conclusions: ECs generate vapor that contains nicotine, but EC brands and models differ in their efficacy and consistency of nicotine vaporization. In ECs, which vaporize nicotine effectively, the amount inhaled from 15 puffs is lower compared with smoking a conventional cigarette.
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TL;DR: The findings of this study are consistent with the idea that substituting tobacco cigarettes with e-cigarettes may substantially reduce exposure to selected tobacco-specific toxicants.
Abstract: Significance Electronic cigarettes, also known as e-cigarettes, are devices designed to imitate regular cigarettes and deliver nicotine via inhalation without combusting tobacco. They are purported to deliver nicotine without other toxicants and to be a safer alternative to regular cigarettes. However, little toxicity testing has been performed to evaluate the chemical nature of vapour generated from e–cigarettes. The aim of this study was to screen e-cigarette vapours for content of four groups of potentially toxic and carcinogenic compounds: carbonyls, volatile organic compounds, nitrosamines and heavy metals. Materials and methods Vapours were generated from 12 brands of e-cigarettes and the reference product, the medicinal nicotine inhaler, in controlled conditions using a modified smoking machine. The selected toxic compounds were extracted from vapours into a solid or liquid phase and analysed with chromatographic and spectroscopy methods. Results We found that the e-cigarette vapours contained some toxic substances. The levels of the toxicants were 9–450 times lower than in cigarette smoke and were, in many cases, comparable with trace amounts found in the reference product. Conclusions Our findings are consistent with the idea that substituting tobacco cigarettes with e-cigarettes may substantially reduce exposure to selected tobacco-specific toxicants. E-cigarettes as a harm reduction strategy among smokers unwilling to quit, warrants further study. (To view this abstract in Polish and German, please see the supplementary files online.)
1,398 citations
TL;DR: E-cigarettes, with or without nicotine, were modestly effective at helping smokers to quit, with similar achievement of abstinence as with nicotine patches, and few adverse events.
986 citations
TL;DR: E-cigarette products are changing quickly, and many of the findings from studies of older products may not be relevant to the assessment of newer products that could be safer and more effective as nicotine delivery devices, so patterns of use and the ultimate impact on public health may differ.
Abstract: Electronic cigarettes (e-cigarettes) are products that deliver a nicotine-containing aerosol (commonly called vapor) to users by heating a solution typically made up of propylene glycol or glycerol (glycerin), nicotine, and flavoring agents (Figure 1) invented in their current form by Chinese pharmacist Hon Lik in the early 2000s.1 The US patent application describes the e-cigarette device as “an electronic atomization cigarette that functions as substitutes [sic] for quitting smoking and cigarette substitutes ” (patent No. 8,490,628 B2). By 2013, the major multinational tobacco companies had entered the e-cigarette market. E-cigarettes are marketed via television, the Internet, and print advertisements (that often feature celebrities)2 as healthier alternatives to tobacco smoking, as useful for quitting smoking and reducing cigarette consumption, and as a way to circumvent smoke-free laws by enabling users to “smoke anywhere.”3
Figure 1.
Examples of different electronic cigarette (e-cigarette) products. Reproduced from Grana et al.1
There has been rapid market penetration of e-cigarettes despite many unanswered questions about their safety, efficacy for harm reduction and cessation, and total impact on public health. E-cigarette products are changing quickly, and many of the findings from studies of older products may not be relevant to the assessment of newer products that could be safer and more effective as nicotine delivery devices. In addition, marketing and other environmental influences may vary from country to country, so patterns of use and the ultimate impact on public health may differ. The individual risks and benefits and the total impact of these products occur in the context of the widespread and continuing availability of conventional cigarettes and other tobacco products, with high levels of dual use of e-cigarettes and conventional cigarettes at the same time among adults4–8 and youth.9–11 It is important to assess e-cigarette toxicant exposure and …
961 citations
TL;DR: The safety and effect of using ECs to help people who smoke achieve long-term smoking abstinence and the main outcome measure was abstinence from smoking after at least six months follow-up is evaluated.
Abstract: Copyright © 2020 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. BACKGROUND: Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol formed by heating an e-liquid. People who smoke report using ECs to stop or reduce smoking, but some organisations, advocacy groups and policymakers have discouraged this, citing lack of evidence of efficacy and safety. People who smoke, healthcare providers and regulators want to know if ECs can help people quit and if they are safe to use for this purpose. This review is an update of a review first published in 2014. OBJECTIVES: To evaluate the effect and safety of using electronic cigarettes (ECs) to help people who smoke achieve long-term smoking abstinence. SEARCH METHODS: We searched the Cochrane Tobacco Addiction Group's Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO for relevant records to January 2020, together with reference-checking and contact with study authors. SELECTION CRITERIA: We included randomized controlled trials (RCTs) and randomized cross-over trials in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention. To be included, studies had to report abstinence from cigarettes at six months or longer and/or data on adverse events (AEs) or other markers of safety at one week or longer. DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methods for screening and data extraction. Our primary outcome measures were abstinence from smoking after at least six months follow-up, AEs, and serious adverse events (SAEs). Secondary outcomes included changes in carbon monoxide, blood pressure, heart rate, blood oxygen saturation, lung function, and levels of known carcinogens/toxicants. We used a fixed-effect Mantel-Haenszel model to calculate the risk ratio (RR) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data from these studies in meta-analyses. MAIN RESULTS: We include 50 completed studies, representing 12,430 participants, of which 26 are RCTs. Thirty-five of the 50 included studies are new to this review update. Of the included studies, we rated four (all which contribute to our main comparisons) at low risk of bias overall, 37 at high risk overall (including the 24 non-randomized studies), and the remainder at unclear risk. There was moderate-certainty evidence, limited by imprecision, that quit rates were higher in people randomized to nicotine EC than in those randomized to nicotine replacement therapy (NRT) (risk ratio (RR) 1.69, 95% confidence interval (CI) 1.25 to 2.27; I2 = 0%; 3 studies, 1498 participants). In absolute terms, this might translate to an additional four successful quitters per 100 (95% CI 2 to 8). There was low-certainty evidence (limited by very serious imprecision) of no difference in the rate of adverse events (AEs) (RR 0.98, 95% CI 0.80 to 1.19; I2 = 0%; 2 studies, 485 participants). SAEs occurred rarely, with no evidence that their frequency differed between nicotine EC and NRT, but very serious imprecision led to low certainty in this finding (RR 1.37, 95% CI 0.77 to 2.41: I2 = n/a; 2 studies, 727 participants). There was moderate-certainty evidence, again limited by imprecision, that quit rates were higher in people randomized to nicotine EC than to non-nicotine EC (RR 1.71, 95% CI 1.00 to 2.92; I2 = 0%; 3 studies, 802 participants). In absolute terms, this might again lead to an additional four successful quitters per 100 (95% CI 0 to 12). These trials used EC with relatively low nicotine delivery. There was low-certainty evidence, limited by very serious imprecision, that there was no difference in the rate of AEs between these groups (RR 1.00, 95% CI 0.73 to 1.36; I2 = 0%; 2 studies, 346 participants). There was insufficient evidence to determine whether rates of SAEs differed between groups, due to very serious imprecision (RR 0.25, 95% CI 0.03 to 2.19; I2 = n/a; 4 studies, 494 participants). Compared to behavioural support only/no support, quit rates were higher for participants randomized to nicotine EC (RR 2.50, 95% CI 1.24 to 5.04; I2 = 0%; 4 studies, 2312 participants). In absolute terms this represents an increase of six per 100 (95% CI 1 to 14). However, this finding was very low-certainty, due to issues with imprecision and risk of bias. There was no evidence that the rate of SAEs varied, but some evidence that non-serious AEs were more common in people randomized to nicotine EC (AEs: RR 1.17, 95% CI 1.04 to 1.31; I2 = 28%; 3 studies, 516 participants; SAEs: RR 1.33, 95% CI 0.25 to 6.96; I2 = 17%; 5 studies, 842 participants). Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate over time with continued use. Very few studies reported data on other outcomes or comparisons and hence evidence for these is limited, with confidence intervals often encompassing clinically significant harm and benefit. AUTHORS' CONCLUSIONS: There is moderate-certainty evidence that ECs with nicotine increase quit rates compared to ECs without nicotine and compared to NRT. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain. More studies are needed to confirm the degree of effect, particularly when using modern EC products. Confidence intervals were wide for data on AEs, SAEs and other safety markers. Overall incidence of SAEs was low across all study arms. We did not detect any clear evidence of harm from nicotine EC, but longest follow-up was two years and the overall number of studies was small. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates. Further RCTs are underway. To ensure the review continues to provide up-to-date information for decision-makers, this review is now a living systematic review. We will run searches monthly from December 2020, with the review updated as relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.
731 citations
TL;DR: In smokers not intending to quit, the use of e-cigarettes, with or without nicotine, decreased cigarette consumption and elicited enduring tobacco abstinence without causing significant side effects.
Abstract: Background: Electronic cigarettes (e-cigarettes) are becoming increasingly popular with smokers worldwide. Users report buying them to help quit smoking, to reduce cigarette consumption, to relieve tobacco withdrawal symptoms, and to continue having a ‘smoking’ experience, but with reduced health risks. Research on e-cigarettes is urgently needed in order to ensure that the decisions of regulators, healthcare providers and consumers are based on science. Methods ECLAT is a prospective 12-month randomized, controlled trial that evaluates smoking reduction/abstinence in 300 smokers not intending to quit experimenting two different nicotine strengths of a popular e-cigarette model (‘Categoria’; Arbi Group Srl, Italy) compared to its non-nicotine choice. GroupA (n=100) received 7.2 mg nicotine cartridges for 12 weeks; GroupB (n=100), a 6-week 7.2 mg nicotine cartridges followed by a further 6-week 5.4 mg nicotine cartridges; GroupC (n=100) received no-nicotine cartridges for 12 weeks. The study consisted of nine visits during which cig/day use and exhaled carbon monoxide (eCO) levels were measured. Smoking reduction and abstinence rates were calculated. Adverse events and product preferences were also reviewed. Results: Declines in cig/day use and eCO levels were observed at each study visits in all three study groups (p,0.001 vs baseline), with no consistent differences among study groups. Smoking reduction was documented in 22.3% and 10.3% at week-12 and week-52 respectively. Complete abstinence from tobacco smoking was documented in 10.7% and 8.7% at week-12 and week-52 respectively. A substantial decrease in adverse events from baseline was observed and withdrawal symptoms were infrequently reported during the study. Participants’ perception and acceptance of the product under investigation was satisfactory. Conclusion: In smokers not intending to quit, the use of e-cigarettes, with or without nicotine, decreased cigarette consumption and elicited enduring tobacco abstinence without causing significant side effects. Trial Registration: ClinicalTrials.gov NCT01164072
641 citations
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...This is not surprising considering that the model under investigation is not very efficient at delivering nicotine [28]....
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TL;DR: The 16 mg Ruyan V8 ENDD alleviated desire to smoke after overnight abstinence, was well tolerated and had a pharmacokinetic profile more like the Nicorette inhalator than a tobacco cigarette.
Abstract: Objectives To measure the short-term effects of an electronic nicotine delivery device (“e cigarette”, ENDD) on desire to smoke, withdrawal symptoms, acceptability, pharmacokinetic properties and adverse effects. Design Single blind randomised repeated measures cross-over trial of the Ruyan V8 ENDD. Setting University research centre in Auckland, New Zealand. Participants 40 adult dependent smokers of 10 or more cigarettes per day. Interventions Participants were randomised to use ENDDs containing 16 mg nicotine or 0 mg capsules, Nicorette nicotine inhalator or their usual cigarette on each of four study days 3 days apart, with overnight smoking abstinence before use of each product. Main outcome measures The primary outcome was change in desire to smoke, measured as “area under the curve” on an 11-point visual analogue scale before and at intervals over 1 h of use. Secondary outcomes included withdrawal symptoms, acceptability and adverse events. In nine participants, serum nicotine levels were also measured. Results Over 60 min, participants using 16 mg ENDD recorded 0.82 units less desire to smoke than the placebo ENDD (p=0.006). No difference in desire to smoke was found between 16 mg ENDD and inhalator. ENDDs were more pleasant to use than inhalator (p=0.016) and produced less irritation of mouth and throat (p Conclusions The 16 mg Ruyan V8 ENDD alleviated desire to smoke after overnight abstinence, was well tolerated and had a pharmacokinetic profile more like the Nicorette inhalator than a tobacco cigarette. Evaluation of the ENDD for longer-term safety, potential for long-term use and efficacy as a cessation aid is needed. Trial registration No.12607000587404, Australia and New Zealand Clinical Trials Register
513 citations
TL;DR: Under these acute testing conditions, neither of the electronic cigarettes exposed users to measurable levels of nicotine or CO, although both suppressed nicotine/tobacco abstinence symptom ratings and increased product acceptability ratings.
Abstract: Background: Electronic “cigarettes” are marketed to tobacco users as potential reduced exposure products (PREP), albeit with little information regarding electronic cigarette user toxicant exposure and effects. This information may be obtained by adapting clinical laboratory methods used to evaluate other PREPs for smokers. Methods: Thirty-two smokers participated in four independent Latin-square ordered conditions that differed by product: own brand cigarette, “NPRO” electronic cigarettes (NPRO EC; 18 mg cartridge), “Hydro” electronic cigarettes (Hydro EC; 16 mg cartridge), or sham (unlit cigarette). Participants took 10 puffs at two separate times during each session. Plasma nicotine and carbon monoxide (CO) concentration, heart rate, and subjective effects were assessed. Results: Own brand significantly increased plasma nicotine and CO concentration and heart rate within the first five minutes of administration whereas NPRO EC, Hydro EC, and sham smoking did not. Own brand, NPRO EC, and Hydro EC (but not sham) significantly decreased tobacco abstinence symptom ratings and increased product acceptability ratings. The magnitude of symptom suppression and increased acceptability was greater for own brand than for NPRO EC and Hydro EC. Conclusions: Under these acute testing conditions, neither of the electronic cigarettes exposed users to measurable levels of nicotine or CO, although both suppressed nicotine/tobacco abstinence symptom ratings. Impact: This study illustrates how clinical laboratory methods can be used to understand the acute effects of these and other PREPs for tobacco users. The results and methods reported here will likely be relevant to the evaluation and empirically based regulation of electronic cigarettes and similar products. Cancer Epidemiol Biomarkers Prev; 19(8); OF1–9. ©2010 AACR.
393 citations
TL;DR: Electronic cigarettes show tremendous promise in the fight against tobacco-related morbidity and mortality and by dramatically expanding the potential for harm reduction strategies to achieve substantial health gains, they may fundamentally alter the tobacco harm reduction debate.
Abstract: The issue of harm reduction has long been controversial in the public health practice of tobacco control. Health advocates have been reluctant to endorse a harm reduction approach out of fear that tobacco companies cannot be trusted to produce and market products that will reduce the risks associated with tobacco use. Recently, companies independent of the tobacco industry introduced electronic cigarettes, devices that deliver vaporized nicotine without combusting tobacco. We review the existing evidence on the safety and efficacy of electronic cigarettes. We then revisit the tobacco harm reduction debate, with a focus on these novel products. We conclude that electronic cigarettes show tremendous promise in the fight against tobacco-related morbidity and mortality. By dramatically expanding the potential for harm reduction strategies to achieve substantial health gains, they may fundamentally alter the tobacco harm reduction debate.
391 citations
01 Jan 2000
TL;DR: The FTC protocol underestimates nicotine and carcinogen doses to smokers and overestimates the proportional benefit of low-yield cigarettes, so FTC-based nicotine medication doses prescribed/recommended for smoking cessation may need to be reassessed.
Abstract: Background: Cigarette smoke yields of tar and nicotine obtained under the Federal Trade Commission (FTC)-specified machine-smoking protocol (35-mL puff volume drawn for 2 seconds once per minute) may not accurately reflect the delivery of toxins and carcinogens to the smoker. We conducted this study to obtain more realistic estimates of exposure to components of cigarette smoke that affect lung cancer risk. Methods: We used a pressure transducer system to evaluate puffing characteristics for 133 smokers of cigarettes rated by the FTC at 1.2 mg of nicotine or less (56 smokers of low-yield cigarettes [<0.8 mg of nicotine per cigarette] and 77 smokers of medium-yield cigarettes [0.9‐ 1.2 mg of nicotine per cigarette]). We programmed measurements from a randomly chosen subset of 72 of these smokers into a piston-type machine to generate smoke from each smoker’s usual brand of cigarettes for assays of nicotine, carbon monoxide, tar, and the lung cancer-causing agents 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and benzo[a]pyrene. The FTC protocol was also used to assess levels of targeted components in the 11 brands most frequently smoked by study subjects. Results: Compared with the FTC protocol values, smokers of low- and medium-yield brands took in statistically significantly larger puffs (48.6 and 44.1 mL, respectively) at statistically significantly shorter intervals (21.3 and 18.5 seconds, respectively), and they drew larger total smoke volumes than specified in the FTC parameters. They received, respectively, 2.5 and 2.2 times more nicotine and 2.6 and 1.9 times more tar than FTC-derived amounts, as well as about twofold higher levels of benzo[a]pyrene and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. Smokers of medium-yield cigarettes compared with smokers of low-yield cigarettes received higher doses of all components. Conclusions: The FTC protocol underestimates nicotine and carcinogen doses to smokers and overestimates the proportional benefit of low-yield cigarettes. Thus, FTCbased nicotine medication doses prescribed/recommended for smoking cessation may need to be reassessed. [J Natl Cancer Inst 2000;92:106‐11]
262 citations
TL;DR: In this paper, the authors used a pressure transducer system to evaluate puffing characteristics for 133 smokers of cigarettes rated by the FTC at 1.2 mg of nicotine or less.
Abstract: Background: Cigarette smoke yields of tar and nicotine obtained under the Federal Trade Commission (FTC)-specified machine-smoking protocol (35-mL puff volume drawn for 2 seconds once per minute) may not accurately reflect the delivery of toxins and carcinogens to the smoker. We conducted this study to obtain more realistic estimates of exposure to components of cigarette smoke that affect lung cancer risk.
Methods: We used a pressure transducer system to evaluate puffing characteristics for 133 smokers of cigarettes rated by the FTC at 1.2 mg of nicotine or less (56 smokers of low-yield cigarettes [
253 citations